Apparatus for sequentially vacuum depositing metal film on substrates



March 31, 1970 R. A. PUDLINER APPARATUS FOR SEQUENTIALLY VACUUM DEPOSITING METAL FILM ON SUBSTRATES 4 Sheets-Sheet 2 Filed bet. 7, 1965 March'3l, 1970 2. A. PUDLINER 3,503,368

APPARATUS FOR SEQUENTIALLY VACUUM DEPOSITING METAL FILM ON SUBSTRATES 1 4 Sheets-Sheet 5 Filed Oct. 7, 1965 53; 4 g I M m w 5T 4 47 March 31, 1970 R. A. PUDLINER 3,503,368

APPARATUS FOR SEQUENTIALLY VACUUM DEPOSITING METAL FILM ON SUBSTRATES 4 Sheets-5110?:

Filed Oct.

APPARATUS FOR SEQUENTIALLY VACUUM DEPOSITING METAL FILM ON SUBSTRATES Richard A. Pudliner, Hokendauqua, Pa., assignor to Western Electric Company, Incorporated, New York, N.Y.,

a corporation of New York Filed Oct. 7, 1965, Ser. No. 493,691 Int. Cl. C23c 13/02, 13/12 US. Cl. 1187 13 Claims ABSTRACT OF THE DISCLOSURE This invention relates to apparatus for sequentially vacuum depositing metal films on substrates, and more particularly, to an apparatus for sequentially moving heating coils into a vacuum evaporation area whereat a succession of metals are evaporated and deposited as thin films on an array of substrates positioned around the evaporation area.

In the manufacture of thin film integrated circuits, ceramic substrates having a plurality of metallic films are used as basic elements upon which the circuits are fabricated. These films are usually of different metals and may be of different thicknesses. Manufacturing difficulties reside in handling these ceramic substrates which are rather brittle and subject to fracture or chipping during transport.

A further dilficulty in the manufacture of multifilm devices resides in the avoidance of contamination between the different deposited films.

These manufacturing difiiculties and others render inappropriate many of the present automatic fabricating facilities. More particularly, conveyor systems for advancing trains of substrates through a plurality of vacuum deposition chambers or areas are likely to result in the fracturing or chipping of the substrates. In other vacuum deposition systems utilizing stationery substrate holders and a plurality of vapor sources which are continuously heated and switched by use of shutters, there is the problem of the vapor sources contaminating each other and the deposited films.

.An object of the present invention resides in a new and improved vacuum deposition apparatus for depositing a plurality of metal films on ceramic substrates.

Another object of the invention resides in a vacuum deposition chamber wherein a plurality of substrates receive deposits from a plurality of different metals without contamination and without danger of fracturing or chipping.

A further object of the invention is the provision of a vacuum deposition chamber having facilities for sequentially rendering a plurality of successive coils effective to deposit a series of metal films on a substrate.

An additional object of the invention resides in a vacuumdeposition chamber together with a carrier for advancing a series of deposition sources into an evaporation area whereat the sources are effective to deposit metal films on an article without contamination of any of the other sources.

' United States Patent 3,503,368 Patented Mar. 31, 1970 With these and other objects in view, the present invention contemplates an apparatus for sequentially advancing a series of metal vapor sources into an evaporation area and rendering these sources eflfective to successively deposit metal films on a group of substrates arrayed about the evaporation area. The evaporation sources may consist of filament coils supporting metallic slugs. These filament coils are circumferentially mounted about a post which also supports a shield to protect each of the coils from contamination. Facilities are provided to sequentially rotate the post and successively energize each coil advanced into the evaporation area. The energization of the coils may be controlled in accordance with the metal to be deposited and also the thickness of the metal films deposited on the substrates which are mounted in removable holders arrayed about the evaporization area.

Other objects and advantages of the present invention will beapparent from the following detailed description when considered in conjunction with the accompanying drawings, wherein:

FIG. 1 is a front elevational view of a rack for holding ceramic substrates to receive deposits of metallic films;

FIG. 2 is a side elevational view showing the rack in an open position to receive the ceramic substrates;

FIG. 3 is a top plan view partially cut away to show a metal deposition apparatus for depositing metal films on substrates held in a number of racks in accordance with the principles of the present invention;

FIG. 4 is a sectional view taken alone line 4-4 of FIG. 3 showing a carrier for advancing metal deposition facilities into position to deposit successive films of metal on the substrates;

FIG. 5 is a sectional view taken along line 5-5 of FIG. 3 showing the details of construction of the carrier and a commutator for selectively engaging coils to vaporize metal to be deposited; and

FIG. 6 is a schematic circuit diagram showing control facilities for operating the apparatus shown in the other views.

Referring to FIGS. 1 and 2, there is shown a rack 10 for receiving three ceramic substrates 11 on which metal films are to be deposited. The rack-10 includes a backing plate 12 on which is mounted a channel member 13 having a guide slot 14 for receiving and retaining the substrates 11. The substrates're st on a bracket 16 extending from the base of the plate 12. A second guide channel 17 is pivotally mounted on a pin 18 projecting from a boss 19 attached to the plate 12. Leaf spring members 21 are attached to the channel member 17 and engage and hold the substrates 11 in the rack 10. The upper end of the guide channel 17 is provided with a bore 22 into which is passed a slide catch pin 23. The slide catch pin 23 is positioned to move within a slot formed in a boss 24 attached to the plate 12. When the guide channel 17 is positioned to move the leaf springs 21 into engagement with the substrates 11, there is a force exerted on the guide channel 17 which acts against the catch pin 23 to hold the pin 23 in its latching position projecting into the bore 22.

Also attached to the plate 12 is a U-shaped handle 26. Further mounted on the back of the plate 12 is a holding bracket 27 for mounting the rack 10 in the vacuum deposition chamber shown in FIGS. 3 and 4.

Referring now to FIGS. 3 and 4, the racks 10 are mounted on a polygon shaped wall 28 so that each bracket 27 overlies the top of the side wall 28. The bottom, of the side wall has mounted thereon resilient clips 29 for engaging the lower sections of the stop brackets 16 and thus insures that the racks 10 are maintained in a "vertical. position within theof-three heating coils 34, 35, and 36 into the evaporation 7 area 32. The carrier 33 includes a conductive platform 37 and three sets of pairs of posts 38 and 39 for supporting the heating coils. Each of the three heating coils 34, 35 and 36 aremounted between the respective pairs of. posts 38 and 39-, so that the heating coils lie upon chords of the circular carrier 33 to define chordal segments extending around the periphery of the carrier Each post 38 interconnects its associated heating coil through the conductive platform 37 to a comomn conductive post 41 (see FIG. axially mounted to an insulating bushing 42. The conductive post 41 is axially positioned with respect to the axisof rotation of the carrier 33 and engages a resilient connecting arm 43, which, in turn, is mounted on a conductive standard 44 that is connected to a strap 45 leading to a source of ground potential.

The lower sections of the other three posts 39 extend through insulating bushings 50 mounted in apertures formed in the plate 37 and engage conductive commutator segments 46 secured in slots formed in an insulating support ring 47. The commutator segments 46 engage a spring-urged copper or carbon brush 48 which, in turn, is connected through a strap 49 to a source of electrical energy. It may be thus appreciated that the contact of the copper brush 48 with a conductive commutator segment 46 results in electrical energy being applied to one of the coils 34, 35, or 36.

In order to protect the coils from contamination while one coil is energized to vaporize a metal, there is mounted on the conductive post 41 a triangular shaped stainless steel shield 51 having angular peripheral edge sections 60-60 which extend between the ends of the heating coils 34, 35 and 36. Also a stainless steel hoodlike shield 55 is supported on the tops of bushings 50 and has a depending flange to skirt the commutator segments 46 and the brushes 48, thus protecting these elements from deposits of the metal vapor.

The metal to be vaporized is either positioned within a heating coil or supported on the coil. Considering coil 36 (FIG. 4), there is shown a folded section of metal 52. Within coil 35 there is shown U-shaped metal slugs 53 which are supported on the convolutions of the coil. The composition of the metal slugs may be different. For instance, the slug within the coil 34 may be a Nichrome alloy and a copper slug may be positioned within the coil 35, whereas a palladium slug may be positioned within the coil 36.

The carrier 33 includes a drive shaft 54 connected to bushing 42 and attached to a six-slotted Geneva wheel 56 (see also FIG. 6) driven by a pin 57 on a disc 58. The 'disc 58 is driven by a motor 59. The Geneva mechanism will impart incremental rotation to the shaft 54 to rotate the carrier 33 and hence, sequentially move the successive coils 34, 35, and 36 into the evaporation area 32. As each coil is moved into the evaporation area, the brush 48 energizes a segment 46 to energize the associated coil whereupon the metal slug positioned within the coil is heated and vaporized. The metal vapor in the evaporation area 32 is uniformly distributed over the substrates 11 held in the arcuate array of racks 10. The metal vapor will deposit as a film on each substrate.

In order to insure the deposit of the metal vapor on the substrates 11, the walls 28 of the evaporation chamber (FIG. 3) are cooled by an undulating conduit 61 attached to the outer walls. Cooling fluid is received through a tube 62 and passes through the undulating conduit 61 and then through an outlet tube 63. In order to insurethat the metal vapors are confined within the chamber, metal plate 66 is mounted on the inwardly projecting handles 26 of the racks 10.

A metallic bell jar 67 is placed over the apparatus and rests on the base 31. A port 68 extends through the base 31 and is connected to a pipe line 69 leading to a vacuum pump. The vacuum pump is operated to evacuate the inside of the bell jar 67 to permit the vacuum deposition process to occur.

Considering now the over-all operation of the apparatus, an attending operator will load substrates 11 into racks 10 (see FIGS. 1 and 2) and then mount the racks on the tops of the side wall 28 (see FIGS. 3 and 4). Predetermined charges of metal to be deposited are loaded in the coils 34, 35, and 36. Next, the bell jar 67 is lowered and the vacuum pump is operated to evacuate the bell The apparatus may be automatically controlled by the circuits shown in FIG. 6. The attending operator will depress a start switch to complete a circuit to a motor driven timer 101 which functions to drive a switch actuator 102 along a screw shaft '103. The timer also drives, through suitable speed reduction gears (not shown), a cam 104 to complete a bypass circuit through a contactor 105 and around the start switch 100. The timer will be operated for the time required to index the carrier three increments and subsequently eifectuate the vapor deposition of the metal on the substrates 11 whereafter the cam 104 will open contactor 105 to interrupt the bypass circuit. The switch actuator 102 first engages and closes a switch 106 to complete a circuit to a relay coil 107 to draw up contactor 108 and complete an energizing circuit of a motor 109. The motor 109 drives through a gear reduction unit 110 a wiper of a variable autotransformer 111 to impress energizing power over a lead 112 through the strap 49, the brush 48, the aligned commutator segment 46, post 39, the coil 34, post 38, the conductive plate 37, conductive post 41, the connection arm 43, the conductive standard 44, strap 45, back over a lead 113 to the autotransformer 111. The relay coil 107 is released by the movement of the actuator 102, but the contactor 108 is maintained closed by a latch 116 of a coil 117 connected in an adjustable voltage sensitive meter device 118 that is, in turn, connected across the leads 112 and 113. The coil 34 and the charge contained therein is progressively heated to vaporize the metal charge and deposit it on the substrates '11. When the voltage output from the autotransformer reaches a predetermined value, the charge will have been completely vaporized, and the commercially available voltage sensitive meter device 118 will detect this predetermined voltage connected across leads 112 and 113. The device 118 will energize the relay 117 to release the latched contactor 108 to disrupt the energizing circuit for the motor 109 whereupon the output of autotransformer 111 is interrupted and restored to the initial condition. The time of energization for the coil 34 is set to be sufiicient to enable a complete vaporization of the metal charge. This operation will be completed prior to the time that the actuator 102 engages a switch 121.

When the actuator 102 closes the switch 121, a circuit is completed to energize the motor 59. The motor 59 drives gears 122 and 123 to rotate the disc 58 and pin 57 to rotate the Geneva wheel 56 degrees. Rotation of the Geneva wheel 56 is imparted to the drive shaft 54 and the coupling 42 to rotate the carrier 33 to position the heating coil 35 in the evaporation area 32. When the actuator 102 moves past the switch 121, the motor 59 is maintained energized by a lobed portion of a cam 126 which closes a contactor 127 to complete a circuit about the switch 121. The cam 126 rotates 120 degrees to present a second low portion to the contactor 127 whereupon the energizing circuit for the motor 59 is interrupted at the same time that the carrier advances the heating coil 35 into the evaporation area.

The actuator 102 now engages a switch 131 to complete an energizing circuit for a relay coil 132 which draws up a contactor 133 to again energize the motor 109. The motor 109 again drives the autotransformer 111 to now progressively energize heating coil 35. The contactor 133 is maintained closed by a latch 134 controlled by a latching coil 135 of a voltage sensitive meter device 136. When the meter device 136'detects a predetermined voltage impressed across the leads 112 and 113 which will occur after the complete vaporization of the metal charge in the heating coil 35, the latching coil 135 is energized to withdraw the latch 134 to release the contactor 133 whereupon the motor 109 is de-energized to interrupt the output from the autotransformer 111. The actuator now engages a switch 137 to again complete the energizing circuit for the motor 59 and, as a result, the carrier 33 is indexed another 120 degrees to move the heating coil 36 into the evaporation area 32. Again the contactor 127 is closed by the now rotated cam 126 to maintain motor 59 energized to enable the 120 degree rotation of the carrier 33.

Shortly after the completion of this rotation of the carrier 33, a switch 141 is closed to energize a relay coil 142 to draw up a contactor 143 to complete another energizing circuit for the motor 109. The motor 109 now drives the autotransformer 111 to energize the heating coil 36 to vaporize the metal charge. The contactor 143 is maintained closed by a latch 144 controlled by a latching coil 146 of a voltage sensitive meter device 147. When the charge in the coil 36 is vaporized, the meter device 147 will energize the latching coil 146 to withdraw the latch 144 whereupon the contactor 143 moves to interrupt the energized circuit or the motor 109. De-energization of the motor 109 interrupts the output of the autotransformer 111 to de-energize the heating circuit for the heating coil 36. Next, the actuator 102 engages a switch 148 to again energize the motor 59 so that the carrier 33 is again indexed 120 degrees to restore the heating coils 34, 35, and 36 to the original position. Following indexing of the carrier 33, cam 104 interrupts the locking circuit for the timer 101. Timer 101 may now be reset for another cycle of operation of the apparatus.

By setting the physical positions of the switches 106, 131, and 141, the energizing circuits for the heating coils 34, 35, and 36 may be set for different time intervals. The time that the heating coils 34, 35, and 36 are energized may be varied to insure sufficient energization to completely vaporize the metal charges. The time for vaporization will depend on the particular metal being used and the amount of metal to be deposited. A group of resistors 151, 152, and 153 may be set to vary the speed at which the motor 109 drives the autotransformer 111 to again vary the voltage output of the autotransformer to control the rate and time of vaporization of the metal charges in the heating coils 34, 3 5, and 36.

It is to be understood that the above-described arrangements of apparatus and construction of elemental parts are simply illustrative of the application of the principles of the invention and many other modifications may be made without departing from the invention.

What is claimed is:

1. In a vacuum deposition apparatus for depositing metal films on a plurality of substrates within a vacuum chamber,

a polygonal-shaped wall arranged within said chamber having surfaces projecting toward a common evaporation area, each sector of said Wall having a clip element thereon for receiving and supporting the bottom portion of a workholder, Y

a plurality of workholders, for holding the substrates,

' each workholder having a bracket at an upper end for mounting over the upper edge of said wall sector and a recessed bottom portion for receiving said clip element,

a plurality of coils mounted within said vacuum chamber for movement into said evaporation area, each of said coils supporting metal to be deposited,

means for moving each succeeding coil within said common evaporation area, and

means for successively heating each succeeding coil advanced into the evaporation area to vaporize the metal and deposit said metal vapor on all said exposed surfaces of said substrates.

2. In an apparatus for depositing a plurality of thin metallic films on a surface of a ceramic substrate mounted in a vacuum chamber,

a rotary carrier,

a plurality of electrical heating coils circumferentially mounted about said carrier for rotating into an evaporation position which is spaced from and aligned with the surface of the substrate on which the films are to be deposited,

' means for incrementally rotating Said carrier to sequentially advance each of said coils into the evaporation position,

a plurality of metals individually positioned within said individual heating coils for evaporation,

means for successively energizing each succeeding coil advanced into said evaporation position to evaporate the metal and deposit it on said surface,

means for locking each coil in said evaporation position in the energized state,

means for varying the power applied to each energized coil, and

means responsive to a predetermined variation in power for releasing said locking means to interrupt the energizing means.

3. In an apparatus for vapor depositing metal on a substrate,

means for supporting said substrate to expose a surface to an evaporation area,

a plurality of coils for supporting charges of metals to be evaporated and deposited on said substrate,

means for successively advancing each succeeding coil into said evaporation area,

means rendered effective following each advance of a coil into the evaporation area for energizing each coil with an increasing voltage to evaporate the metal charge therein, and

means rendered effective upon sensing a predetermined voltage for interrupting said energizing means.

4. In an apparatus for vacuum depositing metallic films on a surface of a ceramic substrate mounted within a vacuum chamber,

a vertical post rotatably mounted to extend into said vacuum chamber,

a plurality of electrical coils for supporting metal to be evaporated,

means mounting said coils about said post with said coils axially positioned in a horizontal plane for successive movement into an evaporation position in alignment with said surface of said substrate,

means for incrementally rotating said post to successively move each coil into said evaporation position,

means for sequentially energizing each succeeding coil advanced into the evaporation position,

means for locking each coil in the energized state,

means for varying the power applied to each energized coil,

means responsive to a predetermined variation of the power for releasing said locking means to interrupt the energizing means, and 1 means rendered effective following each release of a locking means for operating said incrementally rotating means.

5. In an apparatus for depositing a plurality of metal films on a substrate,

means for holding a substrate with a surface spaced from and facing an evaporation area,

a rotary carrier,

a plurality of coils mounted chordally about the periphery of said carrier for advancement into said evaporation area,

a shield having a polygonal cross-section mounted on said carrier and having apex sections interposed between said coils for preventing vapors emanating from a coil in the evaporation area from depositing on all the other coils,

metal slugs positioned on said coils for evaporation,

means for incrementally rotating said carrier to successively advance each coil into the evaporation area, and

means rendered effective following each incremental rotating of the carrier for energizing each succeeding coil advanced into the evaporation area to vaporize the metal slug positioned within the coil.

6. In a vacuum metal deposition apparatus,

a housing having walls surrounding an evaporation area for supporting a plurality of substrates to receive a succession of metal deposits,

a carrier plate constructed of electrically conductive material,

a plurality of first conductive posts conductively mounted upon and spaced equally from one another around the periphery of said carrier plate,

a plurality of second conductive posts insulatively mounted on and extending through said carrier plate, each one of said second conductive posts being spaced from an adjacent one of said first conductive posts to form adjacent pairs of posts spaced about the periphery of said carrier plate,

a plurality of coils, each having one end connected to one of said first posts and having a second end connected to one of said second posts to form chordally extending coils, each of said coils having a charge of metal to be deposited,

means for incrementally rotating said carrier to advance each succeeding pair of posts and the interconnected coils into said evaporation area,

a normally open circuit including a source of power, the carrier plate and the first posts, the connected coils and the second posts, and

means engaging each succeeding advanced section of the second posts extending through carrier plates for completing said circuit through each succeeding second post to successively energize each coil to evaporate the metal charge within the coil.

7. In an apparatus as set forth in claim 6 wherein,

a center post constructed of electrically conductive material rotatably supporting said carrier plate,

an insulating mounting for said center post, and

means coupled to said insulating mounting for imparting the drive of said incrementally rotating means to said center post.

8. In an apparatus as set forth in claim 6 wherein,

a shield surrounds said center post and is positioned to protect all the other coils from metal evaporated from the coil in the evaporation area, and

a second shield overlying said carrier plate and having a depending skirt section around the periphery of said carrier plate.

9. In an apparatus for sequentially depositing metal films on substrates:

a polygonally-shaped chamber having one open end, each section of said chamber having a clip element thereon for receiving and supporting the bottom portion of a workholder,

an array of workholders, each workholder having a bracket at an upper end for mounting over the upper edge of each of said sectors and a recessed bottom portion for receiving said clip element, said workholder supporting substrate surfaces projecting 8 toward an evaporation area in the open end of said chamber, a rotatable carrier mounted within the open end of said carrier, an array of metal vaporizing coil means mounted to extend chordally about the periphery of said rotatable carrier for advancement in the evaporation area, means for incrementally rotating said carrier to sequen- 1O tially advance each of said coil means into said metal vaporizing array, and

means for energizing eachof said into the evaporation area.

10. In an apparatus for vacuum depositing a plurality of metal films on ceramic substrates,

a housing having a polygon arrangement" of walls spaced about an evaporation area,

a plurality of racks having guide channels for receiving substrates,

means for hanging each rack on one wall to expose one surface of each substrate to said evaporation area,

a carrier rotatably mounted adjacent said evaporation area, plurality of coils circumferentially mounted about said carrier for movement into said evaporation area, a slug of metal to be evaporated mounted on each of said coils, means for incrementally rotating said carrier to rotate each coil into said evaporation area, and

means rendered effective following each incremental rotation of said carrier for successively energizing each coil rotated into said evaporation area to vaporize the metal slug mounted on the rotated coil.

11. An apparatus for depositing metal films on' substrates within a vacuum chamber, comprising:

a group of workholders mounted within said chamber for supporting substrates in an array about an evaporation area;

a carrier mounted for rotation within said chamber to move the periphery thereof through the evaporation area;

a plurality of evaporation coils mounted to extend chordally in a spaced array around the periphery of said carrier, each of said coils supporting a slug of metal to be deposited;

means for rotating said carrier to successively bring each of said coils into the evaporation area;

means operated upon advance of each coil into the evaporation area for heating that coil'to vaporize the metal slug supported thereby and deposit the metal vapor upon said substrates; and

shielding means mounted about the central section of said carrier having peripheral edge sections, portions of which extend into' the spaces between adjacent evaporation coils to preclude metal vapors emanating from the coil being heated within said evaporating area from directly impinging upon the other coils not in the evaporation area.

60 12. An apparatus for depositing metal films on substrates within a vacuum chamber as set forth in claim 11, wherein said plurality of evaporation coils comprises three coils mounted in a triangular configuration; and

said shielding means is triangular in shape having apex sections extending between the ends of each adjacent evaporation coil.

13. An apparatus for depositing metal on substrates within a vacuum chamber, comprising:

a group of workholders mounted within said chamber for supporting substrates in an array about and facing an evaporation area;

a carrier mounted for rotation within said chamber to move the periphery thereof through the evaporation area;

coil means advanced a group of three pairs of spaced, electrically conductive posts mounted in a triangular configuration around the periphery of the upper surface of said carrier;

means for connecting one post of each pair to a common ground potential and the opposite post of each pair to an aligned commutator segment mounted on the lower surface of said carrier;

a group of three evaporation coils mounted respectively between said three pairs of posts on said carrier, each of said coils supporting a slug of metal to be evaporated and deposited;

means for rotating said carrier to successively bring each of said coils into the evaporation area;

means rendered effective following movement of each coil into the evaporation area for connecting that coil, through an aligned commutator segment, to a source of electrical energy to heat the coil and vaporize the metal slug supported thereby and deposit the metal vapor upon the substrates;

means responsive to the evaporation of the slug supported by each evaporation coil for initiating operation of said rotating means to move the next succeeding coil into the evaporation area;

a triangular shielding means mounted upon a central portion of said carrier, said shielding means having three flat surfaces, one of which is spaced from and parallel to each of said evaporation coils, and apex sections formed by the intersection of the surfaces which extend between the ends of adjacent evaporation coils to preclude metal vapors emanating from the coil being heated within said evaporation area MORRIS KAPKLAN,

from directly impinging upon the other coils not in said evaporaton area;

a tubular shield mounted upon said carrier and extending down past the commutator segments on the lower surface of said carrier to protect the segments from metal vapors during the evaporation process; and

means responsive to the evaporation of the slug supported by the third successive coil advanced into the evaporation area for precluding further operation of said carrier rotating means and for interrupting the connection of said third coil to the source of electrical energy.

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2,192,862 3/ 1940 Eagley.

2,239,452 4/1941 Williams et al. 11849'.1 X 2,768,098 10/195'6 Hoppe 1184-9.1 X 2,771,055 11/1956 Kelley et al. 11849 X 2,885,997 5/1959 Schwindt l1849 2,948,635 8/1960l Koller 11 849.1 X 3,081,201 3/1963 Koller 1l849 X 3,211,128 10/1965 Potter et al. 11849.1 3,271,561 9/ 1966 Fredler et al 219271 3,336,898 8/1967 Simmons et al. 11849 2,879,188 3/1959 Strull.

Primary Examiner US. Cl. X.R. 

